By MELANIE MCFARLAND, P-I TELEVISION CRITIC

Updated 10:00 pm, Wednesday, July 5, 2006

Somewhere there must be a TV law that dictates all character-driven detective series must create an entertaining quirk or tragic flaw for the central snoop. We have seen said law manifest in the form of Brenda Leigh Johnson's food issues on "The Closer" and, in a sharper example, Adrian Monk's hyperactive obsessive compulsive behavior.

Their success with viewers makes it natural to question whether a series like "Psych" would be too gimmicky to work. Now we have a detective who channels the spirit world -- just like on "Medium"! Only, well, not so much.

Although Shawn Spencer (James Roday) claims to be a psychic, the truth is that he's really great at two things. First, he has an unnerving ability to memorize the smallest details about his surroundings in a few blinks of an eye. He solves puzzles and cooks up schemes by understanding the language of movement and physical reactions in others. Poker players refer to these motions as tells. Shawn knows 'em all.

Second, he truly, deeply enjoys messing with people.

And there you have the essence of this slacker, a man who merrily cavorts through life, solving the occasional crime by watching the evening news. For the reward money, of course.

That last hobby is what gets Shawn into trouble. The Santa Barbara police don't believe him after he accurately tips them about a burglary case. He explains his gift to them at the station; they respond by making him a suspect. To save himself an unpleasant stint in a cell, he rubs his temples, quivers a little and -- hold the phone -- he's a psychic! Yeah, that's it. That's the ticket. A psychic. And suddenly they're interested.

Yes, the central irony of dogged detectives -- truth seekers! -- accepting an amateurish lie over a reasonable explanation is the first clue that something fun and fresh is at work here.

"Psych" is one of those happy collisions of an intelligent script and an appealing cast. Roday's a charmer, nice looking but more charismatic than pretty, and ably paired with "West Wing" alumnus Dule Hill, who plays Shawn's ultra-responsible childhood friend Gus. Hill may not do much more than make Gus shake his head disapprovingly at Shawn's antics, but he's a welcome and necessary passenger here. Every Sherlock must have his Watson, so it's appropriate that a goofball like Shawn would lean heavily on Gus, an uptight pharmaceutical sales representative.

However -- and here's another one of those laws at work -- Shawn is a tremendous disappointment to his policeman father Henry (Corbin Bernsen). Dad honed the boy's skills in the hope of raising a super detective but was stingy with his affection. (Paternal issues. Check.) In one scene, he quizzes the child version of Shawn on the details of the room they're in, eyes closed. How many hats are in the room? What's the name of the waitress who greeted them when they entered?

"That's amazing!" a stranger gushes after a successful demonstration.

"It's adequate," Dad replies, unimpressed.

"Psych" is more than adequate, fortunately for us. This is a series bound to win over "Monk" faithful, who are getting new episodes Fridays at 9, along with viewers starved for genuinely inspired comedy and the cynics who consider those "laws" to be cliches. There are times when one has to respect the law, even that of TV quirks. This is one of them.

Chappelle's leftovers

Knowing what we know now makes the first of what Comedy Central is now calling "Chappelle's Show: The Lost Episodes" a view into Dave Chappelle's discomfort with riches and stratospheric fame, albeit one with jokes.

Chalk it up to the decision (whether his, his ex-co-writer Neal Brennan's or some vindictive corporate entity's) to kick off what should be the show's third season with the comedian taking aim at his favorite subject of the moment: What the success of "Chappelle's Show" was doing to Dave Chappelle.

One skit tackles the downside of his multimillion-dollar windfall, when the simplest transactions bring out the leech in people. On the other hand, now he can finance his greatest revenge fantasies, which really are entertaining.

Sure, you'll laugh loud and long at this first "Lost" episode -- and, obviously, that's what's important. But these episodes have a memorial quality to them and, like fame itself, their impact feels fleeting. Another skit was a weak visual riff on the "Tupac's Not Dead" conspiracy, which is only slightly more clever than, say, a "Blue Collar TV" sketch on Elvis working at a gas station in Omaha.

Or maybe there is something to "Chappelle's" complaint about the content -- not his fears about perpetuating stereotypes (the episode that allegedly touched this off airs next week) but about the quality. The comedian's presence didn't make the second season outstanding -- it was his ability to boil down universal truths, whether about race or class or our strange obsession over Hollywood gossip and imagery, that made us cackle. Now that he is the situation, what happens?

There are only three of these "Lost" episodes, and they'll probably make us feel like mourning more than anything. A groundbreaking series, one worth running home to watch, is history. And no matter how hard Carlos Mencia tries with "Mind of Mencia," which also kicks off a new season Sunday at 10, he cannot match "Chappelle's Show."

Charlie Murphy, who assumes hosting duties along with Donnell Rawlings, pointed out a bright spot: "I happen to know that if it wasn't for Dave Chappelle, you (bleeps) would still be calling me Eddie Murphy's brother." Yes. At least we have that.